The present invention relates generally to curved veneer laminated stock for use in various chair components such as seats, backrests, and armrests. More particularly, the invention relates to veneer stock presenting opposed surfaces, wherein one of the surfaces is curved to suit the primary function of the stock and the opposite surface presents a substantially planer central region that facilitates attachment of the stock to the support structure of the chair.
It is known to construct veneer stock, such as a chair seat, backrest or armrest, by pressing a pile of wood veneer sheets into a desired shape while an adhesive applied between the sheets is allowed to set, fixing the shape of the seat, backrest or armrest. By employing a plywood construction of this type, manufacturers are able to produce a number of different shapes of stock that satisfy the ergonomic and/or design requirements for the stock. For example, in the construction of a plywood seat, the wood veneer sheets are pressed into a profiled shape presenting a curved or saddle shaped upper support surface that comfortably accommodates the seat of a user. Likewise, if the stock is a backrest, the sheets are pressed into a profiled shape presenting a curved support surface that supports a user's back when the user is seated in the chair.
One aspect of the conventional construction is that known stock not only presents a profiled support surface adapted to support the user, but also an opposing mounting surface that is profiled in the same shape as the support surface. Thus, in the construction of a seat, the lower mounting surface of the seat presents a profiled shape that corresponds to the shape of the upper support surface. As a result, numerous problems are encountered. For example, when the conventional construction is assembled on a chair, the bottom or mounting surface is placed against and secured to the support or control mechanism. However, because the surface is not planer, it does not mate flush with the control mechanism, and the fasteners used to secure the seat in place are placed under moment and shear forces that can cause premature failure of the fasteners.
A related problem resides in the failure that can occur in the seat itself due to the non-linear forces exerted on the seat and fasteners due to the non-mating fit between the mounting surface of the seat and the control mechanism. Such mechanical stresses can cause delamination of the wood veneer sheets, cracking of the veneer, deformation, and/or other failure that might require replacement of the seat or chair. By placing spacers between a seat, backrest or armrest and the support structure to which it is affixed, it is possible to alleviate these stresses to some degree, and to reduce rocking of the component. However, the use of such spacers introduces different problems that must be addressed. For example, spacers concentrate the load of the seat on a relatively small area of the support mechanism, increasing the likelihood of failure, and are time consuming to assemble.